Diazotype materials which can be developed by heat and contain an activator precursor having 2-carboxy carboxamide group releasing a strong base during heating

ABSTRACT

The invention relates to new diazotype materials of which the sensitive layer contains, as a base generator, a compound comprising a basic part and an acid part, the acid part being a 2-carboxycarboxamide group and the basic part consisting of an alkali metal cation or alkaline earth metal cation or a tetraalkylammonium cation. 
     These diazotype materials develop rapidly and possess an excellent resistance to ageing.

This application is a continuation of application Ser. No. 403,613,filed July 30, 1982, abandoned.

The present invention relates, by way of new industrial products, todiazotype products which can be developed by heat and of which thesensitive layer contains an activator precursor for the couplingreaction. The present invention also relates to a thermal diazo copyingprocess characterised by the use of the diazotype products of theinvention.

Diazotype products are already known which can be developed by heat andof which the sensitive layer, which is generally a two-component layerand which thus contains a diazonium salt and a coupler, contains anactivator precursor for the coupling reaction, the activator precursoralso being commonly referred to as a base generator. In fact, theactivator precursor generally releases a basic compound, such as ammoniaor a nitrogen-containing organic base, under the action of heat.

Thus, British Pat. No. 998,949 (KODAK, U.S. Priority of 27.06.1960)describes diazotype materials of which the sensitive layer contains acolloidal binder, a diazonium salt, a coupler and at least onethermolabile salt of an organic carboxylic acid and an organic base.After exposure, developing is ensured by heating to a temperaturebetween 60° and 130° C. during which time the salt is decomposed intocarbon dioxide and a basic compound, the latter activating the couplingreaction. As a general rule, the thermolabile salt consists of atrihalogenoacetate of a nitrogen-containing organic base, such aspiperidinium trichloroacetate, which releases carbon dioxide, ahalogenoform (chloroform) and a nitrogen-containing organic base(piperidine) on heating. Volatile compounds are therefore evolved fromthese activator precursors, and these volatile compounds can formundesirable bubbles in the developed diazotype material, which is ofcourse a disadvantage. It is also known that the halogenoform releasedcombines with the diazotype printing products to give a yellowbackground on developing, which intensifies during storage.

U.S. Pat. No. 3,625,693 of RICOH (Japanese Priority of 9.11.1966)describes a diazotype material of which the sensitive layer contains anaryldiazonium salt carrying a free carboxyl group in the ortho-positionto the diazonium group, a coupler, and a base generator which, under theaction of heat, releases a base which initiates and completes thecoupling reaction. The activator precursor, also referred to as a basegenerator, can be urea, thiourea or their derivatives, guanidine or itsderivatives, amides, or alternatively salts of trichloroacetic acid anda basic compound such as ammonia, an amine a guanidine or an inorganicbase.

According to U.S. Pat. No. 3,625,693, the process makes it possible toobtain diazotype materials which are stable on storage, by virtue of theparticular choice of the diazonium compound. However, this is adisadvantage because it considerably limits the possible choice of thediazonium compound.

This U.S. Pat. No. 3,625,693 indeed emphasises the difficulties whichare encountered in practice if it is desired to prepare a two-componentdiazotype material of which the sensitive layer contains a basegenerator in addition to the diazonium salt and the coupler. It is infact stipulated that these diazotype materials generally have a lowstorage stability, which simultaneously results in an increase in thebackground and a weakening of the coloured images.

French Pat. No. 2,056,231 of RICOH (French Application No. 70/20,228)describes diazotype materials which make it possible to obtain anintense black azo image by virtue of the particular choice of thecoupler (a phenol carrying carboxyl groups) and of specific mixtures ofdiazonium salts carrying carboxyl groups. Furthermore, it is indicatedon page 8 that the storage properties of the diazotype material are onlyobtained if the photosensitive layer does not contain alkali generator.

French Pat. No. 2,360,909 (National Registration No. 77/24,157)describes activator precursors comprising an acid part and a basic part,the acid part being an α-sulphonylacetate group. These precursors,which, during heating, release carbon dioxide as a result of adecarboxylation reaction, and also an organic base, can be used indiazotype materials which can be developed by heat, but they exhibit thedisadvantage of releasing carbon dioxide, which can cause the formationof bubbles or holes on the material developed by heat.

Finally, French Pat. No. 2,375,620 of KODAK (National Registration No.77/38,732) describes two-component diazotype materials containing anactivator precursor for the coupling reaction, which consists of a basicpart and an acid part, the acid part being a 2-carboxycarboxamide group.The basic part consists of a protonated nitrogen-containing basic groupsuch as amine and isothiouronium groups. On heating, the activatorprecursors, such as the salt of N,N'-ethylene-bis-phthalamic acid and1,3-bis-(2-aminothiazolin-2-yl)-propane, release the corresponding basiccompound, while the carboxyl group disappears as a result of a thermalcyclisation. Thus, it is observed that the organic base is released byheating, without the evolution of a volatile product, and this is, ofcourse, a distinct advantage. However, these diazotype materials are notwithout any disadvantages. The developing speed on heating, even atelevated temperature, is in fact slow. Furthermore, it has been observedthat the exposed and aged materials subsequently keep rather poorly,while a background colouration is seen to appear and develop, which iswithout any doubt associated with the presence of an excess of basiccompound remaining on the base material after the developing of theimage.

Thus, there was the problem of perfecting new diazotype materials whichcan be developed by heat, which possess a combination of propertiessuitable for ensuring a good commercial development thereof, which have,in particular, a good storage stability, a good sensitivity to theexposure source, a sufficient developing speed at a temperature which isnot too high without release of volatile products, and which at the sametime ensure a good intensity of the colour of the image, a gooddefinition of the image (no appearance of holes or bubbles) and a goodresistance to ageing after exposure and developing.

The present invention achieves this object precisely. New diazotypematerials which can be developed by heat have been found, of which thesensitive layer contains a base generator as an activator precursor forthe coupling reaction generating a coloured trace from a diazonium saltand a coupler, the base generator comprising a basic part and an acidpart, and the acid part being a 2-carboxycarboxamide group, thediazotype materials being characterized in that the basic part of thebase generator consists of an alkali metal cation or alkaline earthmetal cation or a quaternary tetraalkylammonium cation; it is these newdiazotype materials which constitute the subject of the presentinvention.

It has been found that such diazotype materials permit rapid developing.Furthermore, it has been demonstrated that, after exposure anddeveloping, the diazotype materials according to the invention have amuch better resistance to ageing than the diazotype materialscomprising, as activator precursors, a compound comprising a basic partand an acid part, the acid part being a 2-carboxycarboxamide group andthe basic part consisting of a protonated nitrogen-containing basicgroup. A result of this kind is unexpected because the activatorprecursor according to the invention releases a strong base whichtherefore has a high pKa, which is not volatile during the thermaldeveloping treatment, and the presence of which could only be consideredas jeopardising a good resistance to ageing. Furthermore, the existenceof this excellent resistance to ageing seemed unforeseeable in the lightof the prior art and in particular of French Pat. No. 2,056,231.

More precisely, the subject of the present invention consists of newdiazotype materials which can be developed by heat and of which thesensitive layer contains, as an activator precursor for the couplingreaction, a base generator containing a 2-carboxycarboxamide group andrepresented by the general formula (I): ##STR1## in which the varioussymbols represent the following:

R₁, R₂, R₃ and R₄ : a hydrogen atom, a halogen atom or an alkyl orhalogenoalkyl, alkoxy, alkoxycarbonyl, hydroxyl, carbamoyl orcarboxamide group, it being possible for the groups R₁ and/or R₂ toform, with the groups R₃ and/or R₄, a valence bond and/or a divalentgroup forming, with the two carbon atoms to which the groups R₁ (or R₂)and R₃ (or R₄) are attached, a group (L) which can optionally containanother 2-carboxycarboxamide group, and the group (L) being cyclic orpolycyclic or alternatively consisting of a combination of severalcyclic groups joined to one another by a valence bond, a hetero-atom ora methylene or carboxyl group,

r: an integer equal to 1 or 2,

p: an integer equal to 1 or 2 and representing the valence of the symbolR,

R: a valence bond or one of the following radicals:

(a) a monovalent radical consisting of a hydrogen atom, a group --CONHR₅or --CSNHR₅ (R₅ being a hydrogen atom or an alkyl radical), a saturatedor unsaturated, aliphatic or cycloaliphatic hydrocarbon radical or anaromatic radical, these various radicals being optionally substituted byalkyl groups which are themselves optionally halogenated, by halogenatoms, by carboxyl or nitro groups or by urea, thiourea or hydroxylgroups,

(b) a divalent alkylene, cycloalkylene or phenylene radical or acombination of alkylene or phenylene groups joined to one another by ahetero-atom or a group ##STR2## R₅ representing a hydrogen atom or analkyl group,

M: an alkali metal cation or alkaline earth metal cation of valence q ora quaternary tetraalkylammonium cation,

n: an integer equal to 1 or 2 and such that the overall ionic charge onthe base generator is zero.

It is thus observed that the base generator can be a phthalamic acidderivative, a maleamic acid derivative, a succinamic acid derivative ora polyhydrophthalic acid derivative. Obviously, these various basegenerators, which can be mixed with one another, can also contain anysubstituent which does not have an unfavourable effect on thesensitometric characteristics or the other properties of the diazotypematerial which can be developed by heat. These various substituents canbe carried by the groups (L) or (R).

Preferably, the present invention consists of new diazotype materialswhich can be developed by heat and of which the sensitive layercontains, as an activator precursor for the coupling reaction, acompound containing a `-carboxycarboxamide group and of the formula (I)in which the various symbols represent the following:

R₁, R₂, R₃ and R₄ : a hydrogen atom, a chlorine atom or an alkyl oralkoxy group having from 1to 4 carbon atoms, two of the groups R₁, R₂,R₃ and R₄ consisting of hydrogen atoms, it being possible for the groupsR₁ and/or R₂ to form, with the groups R₃ and/or R₄, a valence bondand/or a divalent group forming, with the two carbon atoms to which thegroups R₁ (or R₂) and R₃ (or R₄) are attached, a group (L) which cancontain another 2-carboxycarboxamide group, and the group (L) beingchosen from amongst the following cyclic or polycyclic groups:

a saturated or unsaturated cycloaliphatic radical having from 4 to 6nuclear carbon atoms and optionally substituted by alkyl groups, halogenatoms or COOH or NO₂ groups,

a phenyl or naphthalene radical optionally substituted by alkyl groups,halogen atoms or COOH or NO₂ groups,

a saturated, unsaturated or aromatic heterocyclic group having 4 to 6atoms in the ring, including a heteroatom,

a saturated or unsaturated cycloaliphatic polycyclic radical or aheterocyclic polycyclic radical containing from 4 to 11 atoms, and

a combination of two saturated or unsaturated cycloaliphatic groupshaving from 4 to 6 nuclear carbon atoms, or of two phenyl groups, joinedto one another by a valence bond, an oxygen atom, a group NH or acarbonyl group,

R: a valence bond or one of the following radicals:

(a) a monovalent radical consisting of a hydrogen atom, a group --CONH₂or CSNH₂, an alkyl or alkenyl radical having from 1 to 4 carbon atomsand optionally substituted by halogen atoms, a phenyl radical which canbe substituted by halogen atoms or by alkyl radicals which arethemselves optionally halogenated, or a cyclohexyl or cyclopentylradical,

(b) a divalent alkylene radical having at most 6 carbon atoms or adivalent cyclohexylene, cyclopentylene or phenylene radical, or acombination of 2 to 10 alkylene groups having at most 6 carbon atoms, orof 2 to 10 phenylene groups, joined to one another by --O--, --NH-- or##STR3##

M: an alkali metal cation or alkaline earth metal cation or a quaternarytetraalkylammonium cation, each alkyl group having from 1 to 8 carbonatoms.

Particularly advantageously, the present invention consists of thediazotype materials which can be developed by heat and of which thesensitive layer contains, as an activator precursor for the couplingreaction, a base generator containing a 2-carboxycarboxamide group ofthe formula (I) in which the various symbols represent the following:

R₁, R₂, R₃ and R₄ : a hydrogen atom, a chlorine atom or a methyl ormethoxy group, two of the groups R₁, R₂, R₃ and R₄ consisting ofhydrogen atoms, it being possible for the groups R₁ and/or R₂ to form,with the groups R₃ and/or R₄, a valence bond and/or a divalent groupforming, with the two carbon atoms to which the groups R₁ (or R₂) and R₃(or R₄) are attached, a group (L) which can contain a2-carboxycarboxamide group, and the group (L) being chosen from amongstthe following cyclic or polycyclic groups:

a saturated or unsaturated cycloaliphatic radical having from 4 to 6nuclear carbon atoms and optionally substituted by a methyl radical,chlorine atoms or COOH or NO₂ groups,

a phenyl group optionally substituted by a methyl radical, chlorineatoms or COOH or NO₂ groups,

a saturated or unsaturated heterocyclic group having 4 to 6 atoms in thering, including an oxygen or nitrogen hetero-atom,

a saturated or unsaturated cycloaliphatic polycyclic radical or aheterocyclic polycyclic radical having from 4 to 11 atoms, optionallyincluding an oxygen or nitrogen hetero-atom, and

a combination of two phenyl groups joined to one another by a valencebond, an oxygen atom, a group NH or a carbonyl group,

R: a valence bond or one of the following radicals:

(a) a monovalent radical consisting of a hydrogen atom, a group CONH₂,an alkyl radical having from 1 to 4 carbon atoms, a phenyl radicaloptionally substituted by halogen atoms or by methyl radicals which arethemselves optionally halogenated, or a cyclohexyl or cyclopentylradical,

(b) a divalent alkylene radical having at most 6 carbon atoms or adivalent cyclopentylene, cyclohexylene or phenylene radical, or acombination of 2 to 5 alkylene groups having at most 6 carbon atoms andjoined to one another by an oxygen atom or a group --NH-- or ##STR4##

M: an alkaline or alkaline-earth cation or quarternarytetralkylammonium, each alkyl group having 1 to 8 carbon atoms.

Finally, of all the compounds containing 2-carboxycarboxamide groups andpresented in general terms or as being preferred and advantageous, thesodium, potassium and lithium salts may be mentioned very particularly.

As already stated, the base generators according to the invention arederivatives of phthalamic, polyhydrophthalamic, succinamic or meleamicacids. These various compounds can furthermore be represented by one ofthe following formulae, depending on the valency of R and the valency ofthe cation M: ##STR5##

The various base generators which can be used within the scope of thepresent invention can easily be prepared in accordance with thetechniques of the prior art, for example by reaction of thecorresponding amino compounds with the acid anhydrides, followed bysalification. For this purpose, reference may be made to the article inJournal of the Chemical Society, 127, page 1,791 (1925).

It will also be noted that the nature of the various substituentsthemselves implies the use not only of β-diacids but also of triacids ortetraacids. Thus, for example, a base generator having two2-carboxycarboxamide groups is obtained directly from bis-β-diacids suchas cyclopentane-1,2,4,5-tetracarboxylic acid.

The base generators according to the invention can optionally contain asmall amount of the compounds of the 2-carboxycarboxamide type of theformula I in which the carboxyl groups are not salified. It is obviousthat such mixtures can be obtained directly during the preparation ofthe base generator according to the invention.

The various diacids (or polyacids) which can be used for preparing thebase generators can be succinic, maleamic, phthalic, dihydrophthalic,tetrahydrophthalic or hexahydrophthalic acids or optionallyheterocyclic, polycyclic diacids such as bicyclo[2,2,2]octanederivatives, bicyclo[2,2,1]heptane derivatives,7-azabicyclo[2,2,1]heptane derivatives and 7-oxabicyclo[2,2,1]heptanederivatives. These various acids, which can contain various substituentsincluding another 2-carboxycarboxamide group, and which have alreadybeen defined, are described, for example, in the literature and inparticular in the basic chemical treatises or also in:

Rodd's chemistry of carbon compounds, second edition:

Volume I part D, Chapter 17: aliphatic dicarboxylic acids

Volume II parts A and B: alicyclic compounds

Volume III part E: phthalic acids

Volume IV parts A and F: heterocyclic compounds

or in the well-known encyclopaedia:

Beilsteins Handbuch der organischen Chemie (Beilstein's Handbook ofOrganic Chemistry).

Purely by way of illustration, the following compounds may be mentionedamongst the diacids (or their anhydrides) or amongst the polyacids whichcan be used:

succinic acid and methylsuccinic acid, α,α-dimethylsuccinic acid,α,α'-diethylsuccinic acid, trimethylsuccinic acid, tetramethylsuccinicacid, monochlorosuccinic acid, monofluorosuccinic acid,α,α'-difluorosuccinic acid, α,α'-dichlorosuccinic acid,trifluorosuccinic acid, tetrafluorosuccinic acid and α-nitrosuccinicacid;

maleic acid and dimethylmaleic acid, itaconic acid, citraconic acid,aticonic acid, methylitaconic acid and chloromaleic acid ordichloromaleic acid;

cyclobutane-1,2-dicarboxylic acid and3,4-dichlorocyclobutane-1,2-dicarboxylic acid,3,4-dibromocyclobutane-1,2-dicarboxylic acid,cyclopentane-1,2-dicarboxylic acid, methylcyclopentane-1,2-dicarboxylicacids, cyclopentane-1,2,4,5-tetracarboxylic acid, dihydrophthalic,tetrahydrophthalic or hexahydrophthalic acids and4-methylhexahydrophthalic acid;

polycyclic diacids such as bicyclo[2,2,1]heptane-2,3-dicarboxylic acid,bicyclo[3,2,2]non-6-ene-2,3-dione-8,9-dicarboxylic acid,bicyclo[2,2,2]oct-5-ene-1,2-dicarboxylic acid,bicyclo[2,2,2]octane-1,2-dicarboxylic acid,bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic acid, B1,4,5,6,7,7-hexachlorobicyclo[2,2,1]hept-5-ene-2,3 dicarboxylic acid andtricyclo[4,2,2,0²,5 ]deca-3,7-diene-9,10-dicarboxylic acid;

phthalic acids, namely ortho-phthalic acid, 3-chlorophthalic acid,4-chlorophthalic acid, 3-methoxyphthalic acid, 3,5-dimethoxyphthalicacid, 3,6-dimethylphthalic acid, 4-nitrophthalic acid,3,4,5,6-tetrachlorophthalic acid, 4-carboxyphthalic acid andbenzophenone-3,4,3',4'-tetracarboxylic acid;

the following heterocyclic acids: furan-2,3,5-tricarboxylic acid,benzofuran-2,3-dicarboxylic acid and pyridine-3,4-dicarboxylic acid; and

heterocyclic polycyclic diacids such as 7-oxabicyclo[2,2,1]hept-5-ene,-2,3 dicarboxylic acid.

Amongst the various monoamines or polyamines which can be used forpreparing the various base generators, there may be mentioned ammonia,hydrazine, aliphatic, cycloaliphatic or aromatic primary monoamines,aliphatic or aromatic primary diamines, and polyamines optionallycontaining hetero-atoms, such as the polyamines of the formulae: NH₂--[(CH₂)_(m') --NH]_(m) --H or NH₂ --[(CH₂)_(m') --O]_(m-1) --(CH₂)_(m')--NH₂, m' being an integer between 2 and 6.

By way of illustration, the following may be mentioned in particular:ammonia, butylamine, cyclohexylamine, hydrazine, aniline, chloroaniline,trifluoromethylaniline, toluidine, xylidine,4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether,ethylenediamine, hexamethylenediamine, cyclohexylenediamine and thelike.

Finally, amongst the various base generators which can be used accordingto the invention, there could be mentioned, by way of illustration, thecompounds of the formula I in which the various symbols correspondexactly to the substituents carried by the acid anhydride (or the diacidor polyacid) and the amine (or the diamine) used to prepare them, whichhave just been mentioned by name. Amongst these compounds, the sodiumand potassium salts of N,N'-polymethylene-bis-phthalamic,N,N'-polymethylene-bis-hexahydrophthalamic,N,N'-polymethylene-bis-succinamic and N,N'-polymethylene-bis-maleamicacids may obviously be mentioned very particularly.

The diazotype materials according to the invention can vary in natureand are applied in any field in which the use of a base generator can berecommended and in which the process of developing the coloured image atleast involves a heating step. Thus, in general, this is a dry thermalprocess in which, in addition to the binder, the sensitive layercontains at one and the same time a diazonium salt, a coupler, a basegenerator and, optionally, the various additional compounds well knownto those skilled in the art (acid stabiliser, reducing agent, UVinhibitor, humectant, contrast modifier and th like); this process thusleads directly to a positive.

The diazotype materials can also be those which can be developed by heatand of which the sensitive layer contains a diazonium salt and a basegenerator, the coupler being generated directly by photolysis of thediazonium salt. This process thus leads directly to a negative.

It is also possible to obtain positive images from diazotype productsaccording to the invention, of which the sensitive layer contains adiazonium salt and a base generator, the developing, after exposure,being ensured by a semi-wet process in which the diazotype paper iswetted, under hot conditions, by a solution of a coupler.

Finally, it is also possible, according to the invention, to manufacturediazotype materials which can be used for copying opaque originals by areflex process in which exposure is initially carried out usinginfra-red radiation, and then, in a second stage, the residual diazoniumsalt is destroyed, for example by exposure to intense ultravioletradiation.

These various processes and the corresponding diazotype materialstogether depend, other than on the nature of the base generator, whichis the characteristic feature according to the invention, on thecustomary diazotype printing technique such as described, for example,in the work by J. KOSAR in 1965, entitled "Light-sensitive systemschemistry and application of non silver halide photographic systems". Itis quite obvious that it is also possible to use several diazonium saltsand/or several couplers simultaneously.

In one variant, at least one of the main constituents of the diazotypematerial of the invention can be introduced encapsulated by any materialwhich can be used for this purpose.

One of the preferred diazotype materials according to the inventionconsists of a material of which the sensitive layer contains a diazoniumsalt, a coupler and a base generator. The diazonium salt can vary innature provided that, as described in the abovementioned work by J.KOSAR, the photolysis decomposition products are not themselves acoloured agent or an active coupler. In this context, the variousdiazonium salts having a high coupling activity and an absorptionmaximum which is greater than or equal to 400 nm are suitable. Thesediazos, which are preferably chosen from amongst compounds permittingrapid coupling and consequently highspeed printing, can be diazoniumsalts containing the cation [Z(N₂ ⁺)_(x) ], x being a number equal to 1or 2. The salt can be a chlorozincate, a chloride, a sulphate, asulphonate, a chlorostannate, a borofluoride, a hexafluoride or thelike, without implying a limitation. Z represents a radical whichcontains a benzene nucleus directly joined to the diazo group andcontains from 6 to 30 carbon atoms, and which can be chosen from amongstthe following radicals:

1. monovalent radicals containing a single benzene nucleus and havingthe formula (II) ##STR6## in which a' represents an integer equal to 0,1 or 2 and in which R' represents a hydrogen atom, a chlorine atom, ahydroxyl group, an alkyl group having at most 4 carbon atoms, an alkoxygroup having at most 4 carbon atoms, the group N(R'₁, R'₂) (R'₁ and R'₂representing a hydrogen atom or an alkyl radical having at most 4 carbonatoms), a phenyl, tolyl, xylyl or cyclohexyl radical or a radical SO₃ H,SO₃ Na, SO₂ NH₂ or COOH.

2. monovalent radicals containing two benzene nuclei and having theformula (III) ##STR7## in which a' and R' have the same meaning as thosegiven for the radicals of the formula (II) and in which X represents avalence bond, an oxygen atom, a sulphur atom or one of the followinggroups: ##STR8## R'₁ having the same meaning as that given for theradicals of the formula (II).

3. monovalent radicals containing a heterocyclic radical and having theformula (IV) ##STR9## in which a', R' and X have the same meaning asthose given for the radical (III) and in which Q represents one of thefollowing heterocyclic groups: ##STR10## it also being possible forthese various radicals Q to be substituted by one or two methyl groups.

4. polycyclic radicals (V) chosen from amongst naphthyl, phenanthrenyl,anthracenyl, quinolyl and isoquinolyl radicals.

5. divalent radicals having one of the following formulae: ##STR11## thesymbols R', a' and X having one of the meanings given for the radicalsof the formula (III).

Z will advantageously be chosen from amongst the following radicals:

(1) Monovalent radicals chosen from amongst the following radicals:

1.1. radicals of the formula (II)' ##STR12##

in which a' has the meaning given above and in which R' represents ahydrogen atom, a chlorine atom, a hydroxyl group, a methyl or ethylgroup, a methoxy or ethoxy group, a group NH₂ or --N(R'₁ R'₂) (R'₁ andR'₂ representing a hydrogen atom, a methyl or ethyl radical or a phenylradical) or a radical SO₃ H, SO₃ Na or SO₂ NH₂.

1.2. a radical of the formula (III)' ##STR13##

in which R' and a' have one of the meanings given for the radicals ofthe formula (II)' and in which X represents a valence bond, an oxygenatom, a sulphur atom or a group --NH--, --CONH--, --NHCO-- or --SO₂ --.

1.3. a radical of the formula (IV)' ##STR14## in which R', a' and X haveone of the meanings given for the radicals of the formula (III)' and inwhich Q represents one of the following heterocyclic radicals: ##STR15##

1.4. the naphthyl radical

(2) Divalent radicals having one of the following formulae: ##STR16##the symbols R', X and a' having one of the meanings given for theradicals of the formula (III)'.

By way of illustration, the radicals having one of the followingformulae may be mentioned amongst the radicals Z: ##STR17##

The coupling agent itself can vary greatly in nature. For this purpose,reference may be made to the abovementioned work by J. KOSAR or to thework by Kirk-Othmer, entitled "Encyclopedia of Chemical Technology,"1978 edition, Volume 3--Azodyes--page 387 et seq.. The coupler isgenerally a phenolic compound, which can be a monophenol optionallysubstituted by various groups such as halogen atoms or alkyl, alkoxy,hydroxyalkyl, hydroxyalkoxy, amino, sulphamido, sulpho or carboxylgroups, and/or which can contain urea and thiourea groups; it is knownthat couplers of this type generally give yellow or light browncompounds.

The coupling agent can be a polyphenol or its derivatives produced frompyrocatechol, resorcinol, aminoresorcinol, resorcylic acid andhydroquinone, and containing substituents such as those which have beendefined above in the context of monophenols. The coupler can also be atrihydroxybenzene or one of its derivatives, such as phloroglucinol orits derivatives. The coupler can also be a derivative of phenolic typefrom the biphenyl or naphthalene series; in this context, there may bementioned trihydroxybiphenyls or tetrahydroxybiphenyls, naphthols,hydroxynaphthoic acid and their derivatives, naphthalenediols, thesevarious compounds being optionally substituted by the various groupssuch as defined above, or used in the form of derivatives of theirfunctional groups. Finally, couplers which may be mentioned are variousnon-phenolic compounds such as β-diketones, acetonitriles,cyanacetylamides, sulphonamides, acetoacetic acid derivatives, alkylmalonamates, pyronones, hydroxypyridones, oxyquinolones, pyrazolones,thiophene derivatives and the like.

The use, as couplers, of 2-aryl-2H-benzotriazoles carrying phenolichydroxyl groups may also be mentioned, and the various compounds whichfollow may be mentioned amongst these:2-(2'-hydroxyphenyl)-2H-benzotriazole,5-chloro-2-(2'-hydroxyphenyl)-2H-benzotriazole,5-ethyl-2-(2'-hydroxyphenyl)-2H-benzotriazole,5,6-dichloro-2-(2'-hydroxyphenyl)-2H-benzotriazole,2-(2',5'-dihydroxyphenyl)-2H-benzotriazole,2-(2',4'-dihydroxyphenyl)-2H-benzotriazole,2-(2',4'-dihydroxy-5'-chlorophenyl)-2H-benzotriazole,2-(2',4'-dihydroxy-5'-nitrophenyl)-2H-benzotriazole,5-chloro-2-(2',4'-dihydroxyphenyl)-2H-benzotriazole,2-(2'-hydroxy-5'-methoxyphenyl)-2H-benzotriazole.

The use of couplers of this type is advantageous because the azodyestuffs which result therefrom are particularly stable to light and toUV radiation.

To obtain the different colours required in diazotype printing, it maybe necessary to use a mixture of various couplers and/or of diazoniumsalts. The proportions of the diazonium salt to the coupler are inaccordance with the usual limits which are well known to those skilledin the art, that is to say between 0.3 and 3. As regards the amount ofbase generator, this is usually such that there are from 0.1 to 5 g andpreferably from 0.5 to 3 g of base generator per m² of sensitive layer.

Depending on the diazotype material manufactured, the various usualadjuvants which are well known to those skilled in the art will beadded. Thus, the use of acid stabilisers such as organic or inorganicacids, for example oxalic acid, citric acid, tartaric acid,para-toluenesulphonic acid, phosphoric acid and the like, may bementioned.

Finally, the diazotype materials according to the invention can bemanufactured in accordance with the customary techniques, in monolayersor, optionally, in multilayers, using any suitable base material such aspaper, paper provided with a solvent-resistant layer, polyester,varnished tracing paper or cellulose acetate.

It will be observed that, in the process of the present invention, thebase generator can be coated on the same side as the other main reactiveconstituents of the sensitive layer. Therefore, there is no limitationas regards the choice of the base material, which can be a paper or afilm. This is also an advantage compared with the current processes, inwhich the base generator is applied to the back, which necessarilyentails the use of paper as film is unsuitable.

The diazotype materials according to the invention are exposed, using aUV source, through a transparent or semi-transparent original or by thereflex process. Thermal developing is ensured by heating to atemperature between 80° and 160° C. and preferably between 100° and 140°C.

Finally, a further subject of the present invention consists of a diazocopying process in which a coloured image is created by selectivelyreacting a diazonium salt with a coupler, the process beingcharacterised in that the diazotype materials used are the diazotypematerials according to the invention.

The examples which follow illustrate the invention.

EXAMPLE 1

A precoat dispersion which is well known to those skilled in the art,containing:

    ______________________________________    10% strength dextrin solution                            300    cm.sup.3    Syloid 244 (silica from GRACE)                            50     g    Na salt of N,N'--ethylene-bis-                            80     g    phthalamic acid    water q.s.p.            1      liter    ______________________________________

is prepared.

This dispersion is applied to the surface of a heliographic paper at arate of 12 g/m², using an air knife, and dried.

The diazo solution, containing:

    ______________________________________    citric acid              30    g    thiourea                 30    g    2,3-dihydroxynaphthalene 16    g    4-diazo-2,5-diethoxy-N--phenyl-                             12    g    morpholine    ______________________________________

per liter, is applied to the surface of the precoat at a rate of 15g/m², using a Meyer bar, and dried at 90° C.

After exposure under a positive original, the sheet is developed in athermal developing machine, the heated roller of which reaches 140° C.

A positive blue image of the original is obtained.

Optical density measured using a Macbeth TR/R: 1.25.

Background whiteness measured on a Photovolt: 83.

EXAMPLE 2

This example is the same as Example 1, the Na salt ofN,N'-ethylene-bis-phthalamic acid being replaced, in the precoat, by thetetrabutylammonium salt.

The conditions of surface application and drying are the same and thesensitive layer is the same. After exposure and developing, ablue-violet positive image of the original is obtained.

Optical density: 1.30.

Background whiteness: 86.

EXAMPLE 3

This example is the same as Example 1, the Na salt ofN,N'-ethylene-bis-phthalamic acid being replaced, in the precoat, by theNa salt of N,N'-ethylene-bis-succinamic acid.

Under the same conditions of surface application, coating and drying,and with the same sensitive layer, a blue image is obtained at adeveloping temperature of 125° C.

Optical density: 1.25.

Background whiteness: 85.

EXAMPLE 4

This example is the same as Example 1, the Na salt ofN,N'-ethylene-bis-phthalamic acid being replaced, in the precoat, by theNa salt of N,N'-ethylene-bis-maleamic acid.

In this case, a blue image of the original is obtained at 130° C.

Optical density: 1.20.

Background whiteness: 84.

EXAMPLE 5

The precoat is as in Example 2.

The diazo solution contains:

    ______________________________________    citric acid               20    g    thiourea                  30    g    urea                      30    g    2,3-dihydroxynaphthalene  16    g    N,N'--diacetoacetylethylenediamine                              4     g    4-diazo-2,5-diethoxy-N--phenyl-                              12    g    morpholine    ______________________________________

per liter.

After drying, exposure and printing, a positive black image of theoriginal is obtained in a thermal developing machine at about 140°.

Optical density: 1.

Background whiteness: 83.

EXAMPLE 6

A precoat dispersion containing:

    ______________________________________    sodium casein      30 g    silica             40 g    base generator     80 g    water q.s.p. for 1,000 ml    ______________________________________

is prepared.

This dispersion is applied to the surface of a base material fordiazotype printing, using an air knife, and then dried.

A diazo solution containing the following ingredients:

    ______________________________________    sodium 2,3-dihydroxynaphthalene-                           20 g    7-sulphonate    4-diazo-2,5-diethoxy-N--phenyl-                           12 g    morpholine    citric acid            20 g    urea                   30 g    thiourea               30 g    glycerine              20 g    water q.s.p. for 1,000 ml    ______________________________________

is applied to the surface of the precoat, using a Meyer bar, and driedat 80° C.

After exposure under a positive original, the sheet is developed in athermal developing machine at 140° C. A positive blue image of theoriginal is obtained.

The background whiteness (designated by W) and the optical density(designated by OD) are measured. These measurements are carried out assoon as possible after developing (time 0) and then after ageing for 30days in a black polyethylene envelope.

The results are as follows:

    __________________________________________________________________________                                          AFTER AGEING    BASE GENERATOR                   TIME O                                          for 30 days    ACID PART                BASIC PART                                     W OD   W  OD    __________________________________________________________________________     ##STR18##               Sodium Lithium Potassium Tetrabutyl- ammonium                             Tetraethyl- ammonium                                     82 83 83 82 83                                       1.20 1.00 1.00 1.10 1.06                                            79 82 82 78 78                                               1.05 1.00 1.00 1.10 1.06                             Tetramethyl-                                     83                                       1.00 80 1.00                             ammonium    __________________________________________________________________________

It will be noted that the starting paper has a background whitenessequal to at most 90. Furthermore, the images of which the backgroundwhiteness is less than 75 and in which the optical density is less thanor equal to 0.75 cannot be considered as acceptable.

By way of comparison, an experiment was carried out with a tributylaminesalt of N,N'-ethylene-bis-phthalamic acid. It is observed that the imagedevelops poorly and an increase in the background is produced (OD:0.30).

Furthermore, it is observed that the background continues to increaseduring storage in a black polyethylene envelope.

EXAMPLE 7

The same experiment is carried out as in Example 6, a calcium ormagnesium salt of an N,N'-ethylene-bis-phthalamic acid being used as thebase generator. A coloured image is obtained, the optical density ofwhich is more than 0.75.

EXAMPLES 8 TO 33

Following the procedure of Example 6, various coloured images arecreated by changing the nature of the base generator. The results areshown in the table which follows.

    __________________________________________________________________________    BASE GENERATOR                                      BASIC                                           TIME O    ACID PART                         PART W   OD    __________________________________________________________________________     ##STR19##                        Sodium   1.00     ##STR20##                        Sodium   1.00     ##STR21##                        Sodium                                           82  0.8     ##STR22##                        Sodium                                           78  0.8     ##STR23##                        Sodium                                           84  0.90     ##STR24##                        Sodium                                           84  0.8     ##STR25##                        Sodium                                           82  0.80     ##STR26##                        Sodium                                           86  1.20     ##STR27##                        Sodium                                           87  1.20     ##STR28##                        Sodium                                           82  0.80     ##STR29##                        Sodium                                           87  1.00     ##STR30##                        Sodium                                           81  1.20     ##STR31##                        Sodium                                           88  0.90     ##STR32##                        Sodium                                           85  0.75     ##STR33##                        Sodium                                           77  0.75     ##STR34##                        Sodium                                           83.5                                               0.90     ##STR35##                        Sodium                                           86  1.20     ##STR36##                        Sodium                                           75  0.80     ##STR37##                        Sodium                                           Canary yellow back- ground                                               0.80     ##STR38##                        Sodium                                           83  0.75     ##STR39##                        Sodium                                           82  0.90     ##STR40##                        Sodium                                           86  1.20     ##STR41##                        Sodium                                           86  1.05     ##STR42##                        Sodium                                           85  1.30     ##STR43##                        Sodium                                           85  1.20     ##STR44##                        Sodium                                           82  0.90    __________________________________________________________________________

EXAMPLE 34

The procedure of Example 6 is followed, starting from 100 g/liter of thesodium salt of N,N'-ethylene-bis-phthalamic acid; the citric acid isreplaced by 10 g/liter of p-toluenesulphonic acid. Furthermore, noglycerine is added. A coloured image is obtained, the backgroundwhiteness of which is 84, and the optical density is 1.30. After ageingfor 30 days, the background whiteness is 80 and the optical densityremains at 1.30.

EXAMPLE 35

A first bath, which contains the diazo compound and the coupler:

    ______________________________________    thiourea                   30    g    urea                       30    g    sodium 2,3-dihydroxynaphthalene-6-                               30    g    sulphonate    citric acid                15    g    4-diazo-2,5-diethoxy-N--phenylmorpholine                               20    g    aqueous dispersion of a polyvinyl acetate                               25    cm.sup.3    silica (particle size: 3 to 5μ )                               40    g    polyvinyl alcohol (Rhodoviol 5/270) ®                               20    g    water (amount required for one liter of bath)    ______________________________________

is prepared, and then a second bath, containing the base generator:

    ______________________________________    salt of tetramethylammonium hydroxide                               60    g    of N,N'--ethylene-bis-maleamic acid    aluminium sulphate         5     g    aqueous dispersion of a polyvinyl acetate                               25    cm.sup.3    silica (Aerosil 200) ® 3     g    water (amount required for one liter of bath)    ______________________________________     is prepared.

One after the other, these two mixtures are applied to the surface of apaper base material, on the same side, and dried.

After exposure under a positive original, the sheet is developed in athermal machine, the roller of which is at 130° C.

A positive blue image of the original is obtained.

Optical density: 1.30.

Whiteness: 82.

EXAMPLE 36

A precoat dispersion, containing the couplers:

    ______________________________________    polyvinyl alcohol (Rhodoviol 4/20) ®                               20    g    methyl alcohol             50    cm.sup.3    sodium 2,3-dihydroxynaphthalene-6-                               20    g    sulphonate    N,N'--diacetoacetylethylenediamine                               4     g    citric acid                15    g    aqueous dispersion of a polyvinyl acetate                               25    cm.sup.3    silica (particle size: 3 to 5μ )                               40    g    water (amount required for one liter of bath)    ______________________________________

is prepared, and then a second bath, containing the diazo compound andthe base generator:

    ______________________________________    thiourea                  30     g    urea                      30     g    4-diazo-2,5-diethoxy-N--phenylmorpholine                              20     g    citric acid               5      g    sodium salt of N,N'--ethylene-bis-                              100    g    phthalamic acid    water (amount required for one liter of bath)    ______________________________________

is prepared.

One after the other, these two baths are applied, in order, to thesurface of a paper base material for diazo-type printing, on the sameside, and dried.

After exposure under a positive original, the copy is developed in athermal machine, the roller of which reaches a temperatures of 130° C.

A positive black image of the original is obtained.

Optical density: 1.15.

Whiteness: 82.

EXAMPLE 37

The following bath:

    ______________________________________    citric acid                15    g    thiourea                   30    g    urea                       30    g    glycerine                  10    cm.sup.3    sodium 2,3-dihydroxynaphthalene-6-                               25    g    sulphonate    4-diazo-2,5-diethoxy-N--phenylmorpholine                               25    g    silica (particle size: 3 to 5μ )                               30    g    aqueous dispersion of polyvinyl acetate                               40    cm.sup.3    (Mowilith DC) ®    salt of tetrabutylammonium hydroxide of                               50    g    N,N'--ethylene-bis-phthalamic acid    water (amount required for one liter of bath)    ______________________________________

is prepared.

This mixture is applied to the surface of a paper base material,levelled with an air knife and then dried.

After exposure and developing, a blue positive image of the original isobtained.

EXAMPLE 38

A matting layer consisting of:

    ______________________________________    methyl ethyl ketone      320    cm.sup.3    cellulose acetopropionate resin                             90     g    silica                   30     g    methanol                 180    cm.sup.3    salt of tetrabutylammonium hydroxide of                             50     g    N,N'--ethylene-bis-phthalamic acid    ______________________________________

is coated onto a poly-(ethylene glycol)terephthalate base material at arate of 8 g/m².

After drying, a sensitive varnish containing:

    ______________________________________    methanol                 500    cm.sup.3    cellulose acetopropionate resin                             90     g    tartaric acid            8      g    sulphosalicylic acid     5      g    thiourea                 5      g    diresorcyl sulphide      15     g    4-diazo-3-methyl-N--phenylpyrrolidine                             12     g    ______________________________________

is applied on top at a rate of 4 g/m².

After drying at a temperature of 60°-70° C., the sheet is exposed to UVunder a positive original and developed in a thermal machine at atemperature of 120° C. A sepia positive image of the original isobtained.

EXAMPLE 39

A matting varnish containing:

    ______________________________________    methyl ethyl ketone      320    cm.sup.3    silica                   30     g    cellulose acetopropionate resin                             90     g    methanol                 180    cm.sup.3    tartaric acid            8      g    sulphosalicylic acid     8      g    thiourea                 5      g    diresorcyl sulphide      15     g    4-diazo-3-methyl-N--phenylpyrrolidine                             10     g    salt of tetramethylammonium hydroxide of                             60     g    N,N'--ethylene-bis-phthalamic acid    ______________________________________

is deposited onto a poly-(ethylene glycol)terephthalate base material ata rate of 10 g/m².

After drying at 70° C. and exposure to UV under an original, a sepiacounter-imagewise negative having a good opacity to ultra-violetradiation is obtained by passing the sheet through a thermal machine at120° C.

We claim:
 1. A heat-developable diazotype material comprising a basematerial as a support and a multilayer sensitive layer supported on thebase material and which contains as essential ingredients a diazoniumsalt, a coupler and a base generator as an activator precursor for thecoupling reaction generating a coloured trace from said diazonium saltand said coupler, wherein no more than two of the essential ingredientsare present in any one layer of the multilayer sensitive layer, the basegenerator being a salt comprising a basic component and an acidcomponent, and the acid component being a 2-carboxycarboxamide group,the diazotype materials being characterized in that the basic componentof the base generator consists of an alkali metal cation.
 2. Thediazotype material according to claim 1, characterised in that the basegenerator is a compound of the general formula (I): ##STR45## in whichthe various symbols represent the following: R₁, R₂, R₃ and R₄ : ahydrogen atom, a halogen atom or an alkyl, halogenoalkyl, alkoxy,alkoxycarbonyl, hydroxyl, carbamoyl or carboxamide group, or the groupsR₁ and/or R₂ may form, with the groups R₃ and/or R₄, a valence bondand/or a divalent group forming, with the two carbon atoms to which thegroups R₁ (or R₂) and R₃ (or R₄) are attached, a group (L) which maycontain another 2-carboxycarboxamide group, and the group (L) beingcyclic or polycyclic or or the group (L) consists of a combination ofseveral cyclic groups joined to one another by a valence bond, ahetero-atom or a methylene or carboxyl group,R: an integer equal to 1 or2, p: an integer equal to 1 or 2 and representing the valence of thesymbol R, R: a valence bond or one of the following radicals: (a) amonovalent radical consisting of a hydrogen atom, a group --CONHR₅ or--CSNHR₅, R₅ being a hydrogen atom, an alkyl radical, a saturated orunsaturated aliphatic or cycloaliphatic hydrocarbon radical, or anaromatic radical; or any one of the foregoing radicals substituted byalkyl groups, halogenated alkyl groups, halogen atoms, carboxyl groups,nitro groups, urea groups, thiourea groups or hydroxyl groups; or (b) adivalent alkylene, cycloalkylene or phenylene radical or a combinationof alkylene or phenylene groups joined to one another by a hetero-atomor a group ##STR46## R₅ representing a hydrogen atom or an alkyl group,M: an alkali metal cation or alkaline earth metal cation of valence q ora quaternary tetralkylammonium cation, and n: an integer equal to 1 or 2and such that the overall ionic charge on the base generator is zero. 3.The diazotype material according to one of claim 1, chacterised in thatthe base generator is a compound of the general formula (I) in which thevarious symbols represent the following:R₁, R₂, R₃ and R₄ : a hydrogenatom, a chlorine atom or an alkyl or alkoxy group having from 1 to 4carbon atoms, two of the groups R₁, R₂, R₃ and R₄ consisting of hydrogenatoms, or the groups R₁ and/or R₂ may form, with the groups R₃ and/orR₄, a valence bond and/or a divalent group forming, with the two carbonatoms to which the groups R₁ (or R₂) and R₃ (or R₄) are attached, agroup (L) which can contain another 2-carboxycarboxamide group, and thegroup (L) being selected from the group consisting of the followingcyclic or polycyclic groups: a saturated or unsaturated cycloaliphaticradical having from 4 to 6 nuclear carbon atoms, or said radicalssubstituted by alkyl groups, halogen atoms or COOH or NO₂ groups, aphenyl or naphthalene radical or said radical substituted by alkylgroups, halogen atoms or COOH or NO₂ groups, a saturated, unsaturated oraromatic heterocyclic group having 4 to 6 atoms in the ring, including ahetero atom, a saturated or unsaturated cycloaliphatic polycyclicradical or a heterocyclic polycyclic radical containing from 4 to 11atoms, and a combination of two saturated or unsaturated cycloaliphaticgroups having from 4 to 6 nuclear carbon atoms, or of two phenyl groups,joined to one another by a valence bond, an oxygen atom, a group NH or acarbonyl group, R: valence bond or one of the following radicals: (a) amonovalent radical consisting of a hydrogen atom, a group --CONH₂ orCSNH₂, an alkyl or alkenyl radical having from 1 to 4 carbon atoms, orsaid radical substituted by halogen atoms, a phenyl radical which can besubstituted by halogen atoms or by alkyl radicals or halogenated alkylradicals, or a cyclohexyl or cyclopentyl radical, or (b) a divalentalkylene radical having at most 6 carbon atoms or a divalentcyclohexylene, cyclopentylene or phenylene radical, or a combination of2 to 10 alkylene groups having at most 6 carbon atoms, or of 2 to 10phenylene groups, joined to one another by --O--, --NH-- or ##STR47## M:an alkali metal cation or alkaline earth metal cation or a quaternarytetraalkylammonium cation, each alkyl group having from 1 to 8 carbonatoms.
 4. The diazotype material according to claim 1, characterised inthat the base generator is a compound of the general formula (I) inwhich the various symbols represent the following:R₁, R₂, R₃ and R₄ : ahydrogen atom, a chlorine atom or a methyl or methoxy group, two of thegroups R₁, R₂, R₃ and R₄ consisting of hydrogen atoms, or the groups R₁and/or R₂ may form, with the groups R₃ and/or R₄, a valence bond and/ora divalent group forming, with the two carbon atoms to which the groupsR₁ (or R₂) and R₃ (or R₄) are attached, a group (L) which can contain a2-carboxycarboxamide group, and the group (L) being selected from thegroup consisting of the following cyclic or polycyclic groups: asaturated or unsaturated cycloaliphatic radical having from 4 to 6nuclear carbon atoms or said radical substituted by a methyl radical,chlorine atoms or COOH or NO₂ groups, a phenyl group, or phenylsubstituted by a methyl radical, chlorine atoms or COOH or NO₂ groups, asaturated or unsaturated heterocyclic group having 4 to 6 atoms in thering, including an oxygen or nitrogen hetero-atom, a saturated orunsaturated cycloaliphatic polycyclic radical or a heterocyclicpolycyclic radical having from 4 to 11 atoms, or said radical includingan oxygen or nitrogen hetero-atom, and a combination of two phenylgroups joined to one another by a valence bond, an oxygen atom, a groupNH or a carbonyl group, R: a valence bond or one of the followingradicals: (a) a monovalent radical consisting of a hydrogen atom, agroup CONH₂, an alkyl radical having from 1 to 4 carbon atoms, a phenylradical, a phenyl radical substituted by halogen atoms or by methylradicals or by halogenated methyl radicals, or a cyclohexyl orcyclopentyl radical, or (b) a divalent alkylene radical having at most 6carbon atoms or a divalent cyclopentylene, cyclohexylene or phenyleneradical, or a combination of 2 to 5 alkylene groups having at most 6carbon atoms and joined to one another by an oxygen atom or a group --NHor ##STR48## M: an alkali metal cation or alkaline earth metal cation orquaternary tetraalkylammonium, each alkyl group having from 1 to 8carbon atoms.
 5. The diazotype material according to claim 1,characterised in that the basic component is a sodium, potassium orlithium cation.
 6. The diazotype material according to claim 1,characterised in that the base generator is a compound derived from aphthalamic acid.
 7. The diazotype material according to claim 1,characterised in that the base generator is a compound derived from amaleamic acid.
 8. The diazotype material according to claim 1,characterised in that the base generator is a compound derived from asuccinamic acid.
 9. The diazotype material according to claim 1,characterised in that the base generator is a compound derived from apolyhydrophthalamic acid.
 10. A two-component diazotype materialaccording to claim 1 wherein the sensitive layer comprises aphotosensitive layer containing said diazonium salt and said coupler anda second layer adjacent thereto containing said base generator.
 11. Atwo-component diazotype material according to claim 1 wherein saidsensitive layer comprises a photosensitive layer containing saiddiazonium salt and said base generator and adjacent thereto a secondlayer containing said coupler.
 12. The diazotype material according toclaim 1 wherein the sensitive layer contains said diazonium salt andsaid coupler at a weight ratio of from 0.3/1 to 3/1 and the amount ofbase generator is from 0.1 to 5 g/m².
 13. The diazotype materialaccording to claim 1 wherein the basic component is a sodium cation. 14.The diazotype material of claim 6 wherein the alkali metal cation is asodium cation.